Density functional theory study of the CO adsorption on Cu(111) surface

In this research to investigate the adsorption of CO molecule on the Cu(111) surface , plane wave pseudo potential density functional theory calculations were performed using the generalized gradient approximation (GGA). Nuclei and core electrons were described by ultra soft pseudo potential and the Kohn Sham orbitals were expanded in a plane wave basis set with a kinetic energy cut off of 50 Ry. The surface was modeled using periodic slabs consisting of five atomic layers and four surface unit cells. The adsorption of CO molecule into four different sites ( atop , bridge , hcp hollow , and fcc hollow) on the Cu(111) surface were examined. The adsorption energy, bond length and vibrational frequency of CO molecule at different sites ,the projected density of states, and electron population were calculated and compared. Among different considered sites, the dsorption of CO molecule in the fcc hollow site was favored energetically.